Technologies

The 12MB650 is a high sensitivity midbass driver with 800W program power handling capabilities. The 12MB650 can be used as either a bass/mid driver in compact 2-way reflex enclosures or in high quality stage monitor applications. Eighteen Sound engineers have obtained the best possible results with today's available materials in terms of clean and undistorted LF reproduction at a ultra high SPL, with the lowest possible power compression figure. Its curvilinear paper cone made from a special high strength wood pulp, has been designed to achieve the best possible linearity within its intended frequency range and to control bell-mode resonances around the cone circumference. The cone is carried by a triple roll suspension formed of a linen-like material, which is more resistant to aging and fatigue than traditional materials. The 65 mm (2.5 in) diameter state-of-the-art voice coil is made with edgewound aluminum wire winded over a high strength fiberglas former. This results in an extremely linear motor assembly with a reduced tendency for eccentric behavior when driven hard. Voice coil cooling has been achieved by incorporating airways between the chassis back plate and the top plate of the magnet, allowing heated air from the voice coil and gap to be channeled away and dissipated by the chassis basket. Special attention was given to the optimization of air flow into the gap without introducing audible noise. A special low-density material air diffractor placed into the heatsink acts as a cooling system, increasing the power handling capability and lowering the power compression figure. The magnetic structure has been optimized using FEA CAD resource, maximizing the flux density in the voice coil gap. Due to the increasing use of high power audio systems at outdoor events or in marine environments, the ability to perform properly under inclement weather conditions is a key feature in Eighteen Sound philosophy. Hence, an exclusive treatment has been applied to the cone giving it water repellent properties. In addition, another special treatment has been applied to the top and back plates making the transducer far more resistant to the corrosive effects of salts and oxidization.

Specifications

Design

Parameters

Mounting and Shipping Info

Nominal Diameter300 mm ( in)

Nominal Impedance8 Ω

Minimum Impedance7.2 Ω

Nominal Power Handling1400 W

Continuous Power Handling2800 W

Sensitivity398.0 dB

Frequency Range45 - 5000 Hz

Voice Coil Diameter65 mm (2.5 in)

Winding Materialaluminum

Surround ShapeTriple roll

Cone ShapeCurvilinear

Magnet MaterialFerrite

Woofer Cone TreatmentWeather protected

Recommended Enclosure100.0 dm3 (3.53 ft3)

Recommended Tuning53 Hz

Resonance Frequency48 Hz

Re6.0 Ω

Qes0.24

Qms3.2

Qts0.23

Vas90.0 dm3 (3.18 ft3)

Sd531.0 cm2 (82.31 in2)

Xmax5.5 mm

Mms48.0 g

Bl19.0 Txm

Le0.83 mH

EBP200 Hz

Overall Diameter310 mm (12.2 in)

Bolt Circle Diameter295 mm (11.61 in)

Baffle Cutout Diameter280.0 mm (11.02 in)

Depth143 mm (5.63 in)

Flange and Gasket Thickness14 mm (0.55 in)

Net Weight6.8 kg (14.99 lb)

Shipping Weight7.5 kg ( lb)

Shipping Box332 x 332 x 184 mm (13.07x13.07x7.24 in)

2 hours test made with continuous pink noise signal within the range Fs-10Fs. Power calculated on rated nominal impedance. Loudspeaker in free air.

Power on Continuous Program is defined as 3 dB greater than the Nominal rating.